function  new_co = pitch_rotate(pitch_angle,old_co)
        %new_co = [0,0,0];
        pitch_angle_rad = deg2rad(pitch_angle);%从角度制转化为弧度制
        pitch_matrix = [1,0,0;
                        0,cos(pitch_angle_rad),-sin(pitch_angle_rad);
                        0,sin(pitch_angle_rad),cos(pitch_angle_rad)];
        new_co = pitch_matrix*old_co;
end